Lever sequence control



June 1951 J. M. JACOBSON LEVER SEQUENCE CONTROL Filed 001;. 24, 1947 Joel M. Jacobson INVENTOR.

PATENT AT ORNEY Patented June 19, 1951 UNITED STATES PATENT OFFICE LEVER SEQUENCE CONTROL Joel M. Jacobson, Hagerstovvn, Md., assignor to Fairchild Engine and Airplane Corporation, a corporation of Maryland 3 Application October 24, 1947, Serial No. 781,915

4 Claims. l

The present invention relates to control mechanism and more particularly to improvements in sequence operating devices for switches, levers and the like.

In the control and operation of many devices it is frequently imperative that these devices be operated in a predetermined sequence and a number of complex blocking or interlocking sequence mechanisms have heretofore been proposed to insure the operation of such devices in a predetermined manner. These prior mechanisms have for the most part been complicated, cumbersome and difficult to apply to existing or standard equipment, and the present invention is directed to an improved, simple and elfective means for determining the sequential operation of a pair of switches, levers or similar operating controls.

The improved device of the present invention consists of a pivoted blocking or cam element mounted between a pair of levers and having a form or configuration which will permit the movement of but one lever, preventing the movement of the other lever until the first lever has been moved. In an improved form the device is stamped or cut from a flat plate element which is readily mounted upon a switch panel or other base structure through which the lever elements project and may be operated.

It is, accordingly, a primary object of the present invention to provide an improved sequence control mechanism for switches, levers and the like. A further object of the invention includes the provision of an improved mechanical interfering or blocking element for preventing the movement of a second member before the first member has been moved. It is a further object to provide such a device which is simple and economical to construct and which is entirely safe and foolproof in its operation. A further object of the present invention is directed to providing an improved sequence operating device which is easily and readily applied to a panel or other mounting base between two existing switch or other lever operating members.

This invention contemplates the further objectives of providing an improved blocking or interfering element to predetermine the sequence operation of a pair of controls and which at the same time serves as a visual signal of the condition of these controls as well as to indicate the only movement of which they are permitted by the improved sequence device. Further objects reside in the improved form and arrangement of the sequence controlling element as well as its arrangement and relationship with respect to the control or switch levers with which it is operated. Other objects and advantages of the present invention will occur to those skilled in the art after reading the present description, taken together with the accompanying drawings, forming a part hereof, in which:

Figure 1 is a front elevational view of a panel containing a pair of control switches to which the improved device has been applied;

Figure 2 is a side elevational view of the same as taken along the lines 2-2 of Figure 1;

Figure 3 is an elevational view of the improved device shown in Figure 1 with the first of the switch levers moved and the blocking device moved to freely permit operation of the second switch lever; and

Figure 4 is a similar view of the same showing the second switch lever moved into its operative position.

While the present invention isapplicable to numerous devices, it will be described as applied to a pair of toggle switches for controlling the operation of a pair of remotely located signal lights, to which device it has proven particularly applicable. In aerial operations involving paratroopers or parachute-troops, it is a customary procedure for either the pilot or co-pilot of the aircraft to give the signal to the paratroopers to jump from the aircraft. This signal is usually provided through the medium. of a pair of signal lights, located in the cabin or passenger compartment in full view of the paratroopers and usually comprises one red and one green light. The red light is a caution light to advise the paratroopers to prepare to jump and the green light is the signal to jump.

During the approach run of the aircraft and some time prior to reaching the objective area upon which the paratroopers are to land, the pilot actuates the initial switch to light the red caution signal and when the aircraft reaches the position at which the jumps should start, the pilot throws the switch which lights the green or jump light. It will be obvious that considerable confusion would result in the event the pilot accidentally operated these switches in the reverse order. It is imperative and of the utmost importance that suitable precautionary measures be taken to prevent such inadvertent operation of these switches in the improper sequence and the present invention about to be described insures such satisfactory operation in connection with a parachutejumpers signalling system as well as in other installations. At

the same time it will, of course, be understood that the present invention is not limited to installations of the character described herein which is merely a preferred example of an application of the invention.

Referring now to Figures 1 and 2, the numeral 5 indicates a panel or base support upon which a pair of toggle switches E and I are mounted as by the mounting screws 5a. At a convenient position upon the panel 5, there are mounted the indicating lights ID and l I, and the toggle levers 8 and 9 of the switches 6 and 1, respectively, extend through the front of the panel through suitable apertures l2 and I3 therein. The switches 6 and T are mounted in the customary manner upon the back of the panel 5 with only the operating toggle levers 8 and 9 projecting therethrough, and similarly the indicating lamps ill and II are mounted for the most part on the back of the panel with only the retaining bezel and lens, or bulls-eye, projecting on the outside of the panel.

For the purposes of the present description the lamp will be the red or caution lamp and the numeral II will represent the green or jump lamp. The lamps are connected to their respective switches by suitable wiring and to an adequate source of energy such that operation of switch 6 will control its adjacent indicating lamp ID as well as a corresponding colored signal lamp in the cabin; and similarly, operation of switch 1 will control lamp 1 l and its corresponding cabin lamp. The face of the panel will be suitably marked by on and ofi indicia, as indicated at b and 5c, the toggle levers in Figures 1 and 2 both being in their down or ofi position. The described switches are preferably of the type in which the toggle levers can only occupy an "on or off position, being spring-actuated such that they are automatically thrown to either side of the central or intermediate position. The present invention is not, however, limited to such spring-actuated levers but can also be applied to those which may remain of themselves in an intermediate position. They are shown as of the digit or finger operated type but may also be of the larger hand grasped or pedal actuated types.

A blocking cam or interference element I4 is pivotally mounted upon a pivot bolt IE5 at its lower downwardly extending portion Ma and is separated from the face of the panel 5 by a suitable spacer or washer I6 which is suitably apertured to permit the bolt E5 to be passed therethrough. The element M, which might be described as a swinging cam, is generally T-shape in outline with its pivotal mounting at the lower end of its stem portion and may be constructed of a plastic, metal or other suitable material. The upper portion of the cam element I4 has parallel side faces I! and I8 whichin the neutral or central position of the cam element [4 as shown in'Figure 1, are adapted to fit closely between the side faces of the toggle'levers 8 and 9 respectively.

The blocking or cam element 14 is provided with symmetrically disposed parallel straight side portions H and H! which in the neutral position of the element as shown in Figure l, are disposed close to the inner ends of the toggle switch levers 8 and 9. As shown in the crosssectional view in Figure 2, the surfaces of these side portions are spaced off the face of panel 5v by the washer 16 a suhicient distance such thatthey are disposed outside of and clear the central cylindrical hubs of the toggle levers which hubs are journaled or pivotally mounted in the respective switch housings. The blocking element M has a laterally extending portion at its upper left hand corner, the outer edge of this extending portion being carried angularly into the side face 18 by the inclined camming edge 20. The blocking element It also has a portion removed from itsnormally rectangular upper right hand corner as indicated by the obtuse angular lines 19 and Mia forming this edge of the element.

As indicated above, the lights l0 and II are mounted upon the panel 5, which is disposed in the cockpit of the aircraft convenient to the pilot or co-pilot, and are the indicating lights by which the pilot or co-pilot can determine at a glance as to whether the corresponding signal lights in the cabin of the aircraft are lighted to convey the proper message to the paratroopers. It will be readily understood that the switch 5 will control a circuit within which the light It on the panel and the signa1 light in the cabin will be in parallel such that both are lighted simultaneously as the switch 6 is thrown on, and that the switch 'i, the light II and the corresponding lightin the cabin are similarly operated.

The operation of the presently disclosed mechanism is as follows: As the aircraft is traveling toward its objective, the toggle switch handles 8 and 9 are initially in their downwardly extending 011* positions as indicated in Figure l and the block element M will occupy its vertical central position as shown in this figure. It will be recalled that the caution signal during the approach run is indicated by the red light I!) and the light in the cabin corresponding thereto, and that it is subsequently followed by flashing on the jump or green light H, and the corresponding lamp in the cabin. Accordingly, from the position shown in Figure 1, it is desired that switch 6 be initially operated, and that switch I be thrown on only after the switch 6 has been thrown on. It will be seen from the extending portion 20 of the block element i l and the closely disposed position of the opposite side face IT with the lever 3 of the switch 6 that the lever 9 of switch I can not be moved into the on position, being blocked by the camming surface 20 of the block element which is prevented from rotating about the pivot l5 by immediate contact of the side surface IT with the handle 8. The latter handle however is free to be moved upwardly into its on position, following which the handle 9 may also be moved upwardly into its on position in the course of which it contacts the camming surface 26 and imparts clockwise movement of the element l4 about pivot l5. This movement is permitted by the recessed corner portion I9 of the blocking element which is permitted to move adjacent to and beneath the lever B as shown in the upper right hand corner of Figure 3. After the toggle lever B has been thrown on and the toggle lever 9'has engaged the camming surface Zilto move the element l4 as it also is moved into its on position, all of the elements will assume the positions shown in Figure 4.

In order to again clear the signal andindicating system for the start of a new parachute jumping operation, the switch lever 9 is first moved downwardly into its off position as indicated-in Figure 3'. Similar downward movement of the switch lever 8' causes'it to engage the. camming surface Isa on. me opposite side of the blocking element 14; impartingcounterclockwise movement to this element such that it is pushed aside or returned into its central positionas indicated in Figure l and. the switch lever 8 is permitted to pass downwardly to its off position.

. It will, accordingly, be seen that starting from the initial positionshown in Figure l in which both switches are in the oil' position the cam element M will permit the switches to be actuated in the desired or predetermined sequence only, namely the switch lever B being thrown on first followed by the switch lever 9. It will be appreciated that the cam element l4 may alternatively be inverted in which it is'suspended from its' pivotal mounting, and that in this position it would also provide a predetermined sequence of the adjacent switch levers. The improved blocking or cam element-l4 is not limited to use in a bank of two switches, but can also be I installed between each two switches in a bank or series of switches of an unlimited number. In such multiple installations, the. operation of each individual cam element can be precisely the same as that shown and described herein just so=-long as the desired switchlever is first actuated to permit actuation of the switch lever on the opposite side of the cam element which latter switch lever in turn clears the way for rocking movement of the next cam element, and so on to the end of the series.

It will be understood that the preferred embodimeent of the invention which has been described above as applied to a jump signal control for paratroopers has been selected for illustrative purposes and the invention is not limited to installations of the type which has been described. Other forms and modifications of the invention, both with respect to the general arrangement of its elements and the details of its respective parts, are intended to come within the scope and spirit of the present invention as more particularly defined in the appended claims.

I claim:

1. In a switch lever sequence control installation including an apertured supporting panel and a pair of spaced switch levers mounted upon said panel and having handle portions projecting through said panel apertures for parallel movements between initial and advanced positions, a

sequence controlling blocking element of fiat plate material pivotally mounted upon the face of said supporting panel in an intermediate and contiguous relationship with respect to said lever handle portions, said blocking element being parallel sided with its free end offset with respect to its pivotally mounted end portion, said blocking element having a camming surface and a recessed portion in the region of the advanced position of a first said lever and having a camming surface and a recessed portion in the region of the initial position of the second said lever arranged such that the advance of a second of said levers engages said camming surface and pivotal displacement of said blocking element is blocked by engagement with said first lever handle portion until the first said lever handle portion has been advanced, subsequent to which advance of the second said lever handle portion engages said camming surface of said blocking element and imparts pivotal displacement thereto about its pivotal mounting to a position outside the path of advancing movement of said second lever handle portion and into a displaced position'in which said first lever handle portion in its advanced position is disposed within said recessed portion Of said blocking element and is blocked in its return movement to its initial position until said second lever handle portion has been returned to its initial position.

2. In a switch lever sequence control installation including an apertur'ed supporting panel'and a pair of spaced switch levers mounted upon the face ofsaid panel and having handle portions projecting through said panel apertures for adjacent parallel movements between initial and advanced positions, the improvement of a sequence controlling blocking element of flat plate material mounted upon the face of said supporting pan-e1 in an intermediate and contiguous relationship with respect to said lever handle portions, said blocking element being generally parallel sided and pivotally mounted adjacent an end portion, said blocking element havingacamming surface and a recessed portion formed in the region of the advanced position of a first of said levers, said blocking element having a camming surface and a recessed portion formed in the region of the initial position of said second lever, the said cam ming surfaces and recessed portions of said blocking element being arranged such that the advance of a second of said lever handle portions engagesits c'amming'surface and dis placement of said blocking element is blocked by engagement with said first lever'handle portion until the first said lever handle portion has been advanced, subsequent to which advance of the second lever handle portion engages said camming surface of said blocking element and imparts pivotal displacement thereto about its pivotal mounting to a position outside the path of advancing mavement of said second lever handle portion and into a displaced position in which said first lever handle portion is disposed within said recessed portion of the head portion of said blocking element and is blocked in its return movement to its initial position until said second lever handle portion has been returned to its initial position, the said blocking element being pivotally mounted on the exposed face of said panel between and below said switch lever handle portions in a, position in which it serves as visual signal for assisting the operator in determining the proper sequence of operation of the lever handle portions.

3. In a sequence control installation for a pair of operating levers movable in adjacent parallel paths between initial and advanced positions, the improvement of a blocking member disposed intermediate the parallel paths of said operating levers and movably mounted for displacement by either one of said levers into the path of the other said lever, said blocking member having dissimilar lateral edges each contiguously disposed toward its respective adjacent operating lever for engagement thereby, said blocking member having an elongated lateral edge adjacent a first of said operating levers in the region of the initial position of said lever, said blocking member having an indentation in the region of the advanced position of said first lever, the opposed second said lateral edge of said blocking member having an indentation in the region of the initial position of the second said operating lever and having its lateral edge uninterrupted in the region of the advanced position of said second lever, said operating levers and said intermediate blocking members being arranged in such manner that said second lever can only be advanced subsequent to thezadvancev of said firstlever whereby displacement :of said blocking member is permitted-by the said'indentation at said advancedxposition-oisaidfirst lever. V

1 4. Ina sequence controliinstallation for a pair of operating levers movable in adjacent. parallel pathsbetween initial andiadvanced positions, the improvement of a blocking member disposed intermediate the 'parallelpathsof said operating levers andmovably mounted fordisplacementby eitherjone of said levers-into-the path of theother said lever, said-blocking member having dissimilar opposite lateral edges 'eachcontiguouslye-disposed toward the respective operating lever for engagement-thereby, said blocking member having an elongated lateral edge adjacent a first of said operating levers in the region of the initial position ofsaid lever and having an indentation in-theregion of the advanced position of said first lever, the opposedsecond .s aid lateral edge of said blocking member having an indentation in. the\ region of the initial position of the second said operating lever and having its lateral edge uninterrupted in the region of the advanced position of said second lever, said operating levers and said intermediate blocking member being arranged in such manner that saidsecond lever can only be advanced subsequent to the advance of said :firstglever whereby displacementof said blocking member is permitted by the said inden- 30 i8 tationat said advanced-position of said-first lever, and angularly disposed-camming portions-interconnecting each said opposed lateral-edgeof :said

blocking member with itsrespective indentation 1 edge in such mannerthat said blocking member is automatically displaced laterally by engagement of; themespective operating lever with its corresponding camming-portionn JOEL M. JACOBSON.

RErE iEfioEs" lorrnn Thefollowing references are of record in the 'file of this patent:

\ u UNITED strn'rns PATENTS 

